Process of producing soft luster artificial silk



Patented AM, 1 40' a sigimi? ;to f American Bemberg Corporation, I cw r-Y ork, N. XL, affcorporation of Delaware No: Drawing; Application dune-5,1935, Serial "No.q.'25',129.,f Renewed August l vmGermany June 22,119 3 1 es, 1939 In J plants, (c1. lls- 54) l The. present invention relates to axprocess off producing soft-luster pro ducts, such as artificial silk, from cuprammonium' cellulose; solutions. I, The primary object of this invention has to dowith the spinning of "cuprannnoniumcellulose solutions into funnels Withoutthe assistance of special delustering 'agents,-and without a delustering after treatment of'the finished, artificial Another object-*of'this' invention relates to the? formation of a brittle surface: skin-ion acellulose: filament or'yarn which,subsequentlyjis ruptured by stretching in the fun the addition'of a predeterminedamountof an acid substance, su'ch as' an; or anammonium salt', to'the washwater, circulati-ngfin the funnel,

to 'form soft-luster 'ciiprammonium "cellulose products.

, Other objects o f thisinvention will become a study apparent to those skilled-in the art from of the following specification. 1 i

It has been foundby experimentation that soft-luster filaments and yarns can be producedfrom cuprammonium cellulose solutions by admixing suchan amountof. an acid substance to the precipitating water that the freshly precipi- It has, furthermore, been found that itbecomes I impossible to -form continuous filaments or suing from the funnel, acquires a neutral or acid reaction. For this reason, the present invention.

- such solutions. Any suitable ammonium-salt or acid, such as sulphuric, tartaric, oxalic, "acetic,

citric, formic acid,,etc., may be used in combina-] tion withwater providedits amount is regulated,

as setrforth above. The optimum, minimum and? maximum amount of the acid substance to be; added to agiven amountio'f water must be varied,

since it depends upon anumber of factors, such as the composition ofthefcuprammonium ,cellu lose solution per se, the speed of spinning, the

purity and temperature of the precipitating solution in the funnel, etc. By using, for example,

atcup rammonium cellulose solution containing about 8% of cellulose, 8% of ammonium hy j-p I -simplified and rendered more efiicient, and somedroxidegand 3%. of copper, and spinning 'itto a thickness of 120 deniers at a speed of 30 meters "yarns, etc. I

,A third object of this invention has to do with 60000. per minute' (30 C.) the maximum addition of sulphuric acid, for example, is about l grams per -liter cf precipitating water. The additionof about- 3 gramsof sulphuric acid to. one i liter of water still allows the formation of slightly i alkaline filaments-and threads, although the precipitating (funnel) water haswan acid reaction. Inthis manner, soft-'luster' cellulosic products can be, produced "in the form of continuous filaments,

per'minutewith a water consumptionof about ,The precipitatingwatenas stated above, may

contain anaci'dwcompound, i. e., an inorganic or organic acid or an ammonium compound, which 'does not-deleteriously afiect'the precipitated cell'ulose\ during:the formation and rupturing of'its brittle surface skin by-stretching the-cellulosic product 'in' .saidprecipitating' waten- Although the aforementioned ammonium compounds assist in coagulating the cellulose" and allow the formation per se of soft-lusterproducts when being present in the precipitating water, they do not create the same feffect as'the equivalent amount I of a free acid. Thus, it has been found that the addition of an acid in combination'with an ammonium compound to the precipitating water may be larger than that one of: a free'acid, part compound in stoichiometrical proportion. For this reason, it is possible to spin successfully ph'ate, although these solutions cannot be spun inywater containing more than} grams of free sulphuric acid per liter. The maximum addition of ammonium sulphate is about '5 grams per liter of-water containing about 2, grams of sulphuric acidlv v p Special advantages are obtained by using the precipitating solutions, set forth above, in combottom of the funnel and recirculated to its: top

These troubles, however, are eliminated by using and recirculating acid precipitating water in accordance with my present invention; In" this manner the conventional -circulation process is timesit becomes even unnecessary to use softened tated cellulose has still an alkaline reaction upon -O which having been replaced by an ammonium v I leavingthespinning funnel and-not anacid one.

water, obtained with the assistance of permutlte, etc, since the unfavorable efiect of calcium bicarbonate can be eliminated by the addition of small amounts of an acid to hard water.

Example A cuprammonium cellulose solution, containing about, 8% of cellulose, 8% of ammonium hydroxide and 3% of copper, isspun in a funnelv in accordance with the conventional stretch? spinning process under the following conditions:

Total titrenni deniers' 120 Spinning speed per minute -meters 30;;

Water consumption per minute cc 600 7 Temperature, of precipitating solution 0;- 30

The aqueous precipitating water contains about 3 "grams of sulphuric acid per literof water (soft The filaments water obtained with; permutite). and yarns obtained are of soft-luster. r

Modifications of the present invention will be readily recognized by those skilled in the art, and, it..is desired to include all modifications, coming withinthe scope of the appended claims.

What isclaimed is: ,7 l. In the process of producing soft-luster products, thejstep which comprises-spinning a cuprammonium cellulose solution under stretching in aiunnel containing Water and an'acid to precipitate cellulose therein, said acid being present insaid water in such an amount that the precipitated cellulose remains slightly alkaline upon leaving said funnel.

2. In the process ,of producing, soft-luster products, the step which comprises spinning a cuprammonium cellulose solution under stretch ing in a funnel containing hard water and an acid to precipitate cellulose therein, said acid being present in said water in such an amount that the precipitated cellulose remains'slightly alkaline upon leaving said funnel.

- 3. In the process of producing soft-luster products, the step which comprises spinning a cuprarnmo nium solution under stretching in water containing; about 2 to 4 grams of sulphurlc acid per liter.

, 4. In the process of producing soft-luster products, the step which comprises spinning a :cuprammonium cellulose solution containing about 8% cellulose, 8% of ammonium hydroxide and 3% of 'copper under stretching in a funnel containing .water'and about 0.2% of sulphuric acid, said cellulose-solution being spun at a speed of about 30 meters per minute.

5. In the process of producing soft-luster products, the step' which comprises spinning a cuprammonium cellulose solution under stretchingina funnel containing water, an acid and an acid compound to precipitate cellulose therein,

said acid and. acid compound being present in said water in such an amount that the precipitated 'celluloseiremains slightly alkaline upon leaving said funnel.

6. In the xprocess of producing soft lu'ster products, the step which comprises spinning a cuprammonium cellulose solution uncler'stretchingin' a iunnelcontaining water, about,0.2%yof sulphuric acid and about 0.3 to 0.5% of ammonium sulphate.

a AUGUST HARTMANN. 

